Boost-Buck Regulator Device

Hello Jim,

Sure but that is cumbersome. A 'no worries' product would be nice where people can tie down their aircraft and just forget about battery self discharge. But AFAICT the regulatory burden and cost is so high that many of those ideas never make it. One method of getting a foot in the door would be to begin marketing in countries with lesser bureaucratic hurdles. That's how we do it in medical.

Regards, Joerg

Hello Jim,

Provided that those little solar cells are cheap enough the easiest method might be to design it for winter time and do some shunt regulation in summer. SEPIC should work as well but EMC needs to be muffled or people will ask where that 'weeeee' sound on their radio comes from.

Regards, Joerg

Hello Jim,

That is a great option. One of our neighbors went a step further and is currently building a pretty large four seater in his garage, Heathkit style.

How do you get insurance in case one of the kits is being blamed for causing some major trouble?

Regards, Joerg

It's simple. The guy's a loon. There is no lead-acid battery that could be damaged by a 150 mA trickle charge. (at least, not airplane-battery-sized!) I almost cooked my DieHard the other day - there were raindrops, so I went out to close my car windows. To close my car windows, I have to turn on the ignition switch, unlike the headlights, who are on their own circuit.

Anyway, I turned on the ignition, raised the windows, closed the rain roof, and went back inside.

I forgot to turn the ignition off.

Next day, the car is sitting there with a "dead" battery. It turns out, the shop has a handy-dandy Sears 10A battery charger in the utility closet. So, I hook this 10A charger up to the dead DieHard, and turn it on. Ten Amps, it reports. So, I figure, it's probably about a 55 Ah DieHard, so I'll let it sit and charge for a couple of hours, and go check on it. About two hours later, I go check (well, maybe three hours), and the battery way _sizzling_. Actually, there was some gas escaping from at least one cell, making a sort of sizzling noise, so I shut down the battery charger and start fretting about whether I've killed my DieHard.

No worries! Next day, I go out and the car just starts right up, and everything is copacetic. I even get a very solid 13.6 on my dashboard voltmeter. :-)

So, if your airplanes are packing batteries that can be damaged by a

Good Luck! Rich

This makes me wonder, just in a speculative vein, of course, if I could take one of those solar panels off of one of those solar yard path light things, and slap it on the roof or cowl or mid-fuse of a Cessna or Piper, and declare it an "experimental aircraft?"

;-) Thanks! Rich

OK, you win.

But I'm still available to solve your problem for you, at $160/hour, plus travel and expenses.

And you're still a thief.

The ball is in your court.

Cheers! Rich

Or disconnect it when voltage rises too much.

Thomas

Another way to go would be a diversion controller, where a FET or relay turns on a load when the battery voltage goes above a max threshold. This will hold the battery voltage down so it doesn't get overcharged. Build some hysteresis in so it will PWM the switch.

Of course you can buy combination PWM series or diversion charge controllers with multi-stage charging.

If your battery's amp hour rating is, say, 1/200th larger or so than your solar panel's available output current (at the battery voltage) then you may not be even able to overcharge that battery anyway.

A 150 mA output PV panel might be good for floating a fully charged

boB

It's done all the time. John Denver, anyone?

How about the "Experimental Aircraft Association"?

FWIG, it's not hard to get such insurance. Liability isn't all

Have a look at this single inductor buck boost Bit of an overkill but I like it.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

Go talk to the Concorde Aircraft Battery company, asshole. Be sure to specify recombinant gas battery. It is their engineer's data upon which my battery charger designs have been based.

Jim

Sorry, forgot the full sig line.

Jim Weir Airframe and Powerplant Mechanic, Inspection Authorization Commercial/Instrument Pilot, Glider and Airplane Flight Instructor, Glider and Airplane Certificated Ground Instructor.

And no, I'm not s*****ng you. Go read the goddamned rule for yourself.

Jim

Try a DC/DC converter from Synqor

Hello Keith,

Have you ever tried to get that type of insurance? I can tell you from my own experience that there are certain categories where the answer is by default "decline to quote". And I've tried pretty much all US carriers.

Regards, Joerg

Certainly there are some insurances that are harder to come by than others. No, I haven't tried to get insurance on experimental aircraft, but I've known several who have. It's quite likely that State Farm (or whatever) won't write such a policy but I gave you a link to a site where they *will* write such insurance. They're likely a self-insured pool though.

Hello Keith,

What I meant was insurance for the company making or designing the electronics kits. Then you are talking to the big ones such as agencies that contract with Lloyds. Try it, and good luck. Been there, done that, didn't work.

Regards, Joerg